1. Field of the Invention
The present invention relates to lumber sawing devices and more particularly to a log sawing attachment for a chain saw for cutting uniform thickness boards.
2. Description of the Prior Art
While several lumber making attachments for chain saws have been devised, the most closely related device to the present invention is that taught by U.S. Pat. No. 3,225,799 to E. A. Hayden, et al. for a LUMBER SAWING ATTACHMENT FOR PORTABLE CHAIN SAW issued Dec. 28. 1965. That device was manufactured for many years by the present inventor's company and proved to have numerous defects which made it uneconomical to sell.
In operating the Hayden device, a flat cut is effected in a log by first nailing a board to the top of the log and then guiding the rollers along the top of the log to make a flat cut through the wood. Thereafter the rollers are rolled along the flat cut to effect the next lower flat cut. This process is repeated until the whole log has been cut into boards. The thickness of the cut can be adjusted simply by turning the hand wheels to move the rollers closer to or away from the cutter bar of the chain saw.
One of the biggest problems with the Hayden device is that the rollers which were intended to permit the saw to effect a straight cut through the wood did not achieve that result. The rollers would, when traversing the log, roll up and over any sawdust encountered on the top of the log rather than pushing it aside and thereby caused an irregular cut through the log as a result of the sawdust bumps being traversed.
Another major defect with the device was the cost of manufacture. It had too many machined parts which simply priced it out of the marketplace. The rollers were heavy and expensive; the screw threads were too expensive to make; the edge guide rollers were too expensive; the whole machine proved impractical from an economic point of view.
The Hayden device required the saw bar of the chain saw to be drilled in order to mount the attachment of the chain saw. This disadvantage proved a sales block for the reason that users in the field simply wanted to easily mount the device on the chain saw and did not care to provide the facilities for modifying the cutter bar in order to secure the attachment to it.
Other problems during the manufacture and use of the device caused it to be virtually an unsaleable machine. In order to overcome these defects a completely new design was required.